How "much" of air consumption is physiology? How to improve consumption?

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purbeast

Contributor
Messages
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Location
Rockville, MD
# of dives
25 - 49
I went on my 5th and 6th post-certification dives 2 days ago here in Turks and Caicos. They were my first "real" dives after certification that I went to any depth. My prior 4 were in the Keys to depths of like 25' max.

When I got certified I did my OW and AOW at the same time, so total dives to date (aside from DSD) is about 15. I know I'm far from a "finished project" as far as my air consumption goes and that I can improve, but I was just curious about how much more people can "improve".

Again, I preface this knowing I am a noob and can definitely improve.

In my OW and AOW training I was always one of the first to get low on air. My last dive in AOW my instructor told me to concentrate on breathing slowly and consciously think about it, and he wanted me back with 800psi or more at the end of the dive. I made it back with like 1100 or so which was good and I felt I improved.

2 days ago I did guided dives to 65'. It was the guide, myself, and another woman. The woman was experienced but hadn't dove in over a year she said, but she was also probably 100lbs wet. I am 200lbs with an athletic build and probably 12-15% body fat. People say I'm built like a line backer.

I bring that up because the first dive, the total time was 31 minutes when I go back to my dive computer. The guide went back down with the other lady and they were like 45 minutes total maybe. The second dive I was 35 minutes, and concsiously tried to work on breathing. I had 500 or so psi when I got back to the boat after both dives. On the second dive, the guide and lady in the group were down for 62 minutes total. They were the last to come back to the boat.

I then talked with my guide about it and he started to say how physiology comes into play at some point. He brought up how my build I am just heavier with more muscles, and need more oxygen to flow through my body. Whereas the other lady was around 100lbs or so and just doesn't require as much oxygen. The guide was a pretty slim male probably 170lbs or so.

Now I know that I can clearly work on breathing, but I just wonder how much more I can improve. I'm looking for tips to improve on it as well. I also have asthma which is super controlled and I've "grown out of it" as I've gotten older, but I am still on Advair which I use a few times a week. I sometimes use that as excuse to myself as maybe why I use more air but I know it's just that - an excuse.

The past 2 dives I was anxious prior to getting in the water, but as soon a I got in down to 60 ft I was SUPER comfortable. And then literally about 1 minute after being in water and we got our bearings, a shark swam right between us and I was super calm and collective and it was so cool. But I never once felt "anxious" or flustered in either of these dives, but my breathing was just so inefficient I feel.

So anyone have any pointers as to what I can work on or realistically how much better I can get it? Would being able to be down an hour at 60' be something realistic for someone of my stature? The guide said he can easily do an hour down there (and did) so I am assuming that I can improve significantly, even if it was closer to like 50 or 55 minutes.

And just FYI, as someone who's never done a wall dive other than my deep dive, it was pretty dang cool and we saw some awesome sea life down there. We saw 2 spotted eagle rays which apparently they said is not very common to see them together. I just wish I could have done more dives!
 
Indeed, your own physiology will set a lower limit on your gas consumption. There is no way you'll ever consume as little gas as a small person. Beyond that, the big things are to work on your skills and make sure you are solid. This means being in trim, not over weighted, not sculling with your hands, and taking your time and kicking slowly.

Regarding being down an hour at 60', it might be possible for someone of your build, but it also depends on what kind of tank we're talking about. On an Aluminum 80, you might not ever see an hour at 60'. With a 100 cf tank, it's very possible. As a big guy, just consider stepping up to a larger tank.
 
I think that you are overthinking about this and just need to get more experience. My husband and I were both air hogs in the beginning, but with lots of diving we improved a lot. Now we finish dives because we get near our NDL, but still have lots of air left. We also try to keep as fit as we possibly can, which really helps. Before we learned to dive I had lost possibly 14 pounds or more. This also made a big difference.

Just do as much diving as you possibly can and when you are not diving get out there and get as much exercise as you can.

Best fishes x
 
Muscle fibers doing any work use O2. Relax as much as possible, use as few muscles as you possibly can. Use your arms as little as possible. Any anxiety causes muscular tension, burns O2. You probably have 3-4 times as much muscle as a 100lb woman, you prob can't compete with her in air consumption, but you can get better and better. I would just use relaxed normal breathing. If you are attacked by a Kraken you will have to fight, and your air consumption will go up.
 
Indeed, your own physiology will set a lower limit on your gas consumption. There is no way you'll ever consume as little gas as a small person. Beyond that, the big things are to work on your skills and make sure you are solid. This means being in trim, not over weighted, not sculling with your hands, and taking your time and kicking slowly.

Regarding being down an hour at 60', it might be possible for someone of your build, but it also depends on what kind of tank we're talking about. On an Aluminum 80, you might not ever see an hour at 60'. With a 100 cf tank, it's very possible. As a big guy, just consider stepping up to a larger tank.
My diving is primarily going to be vacation diving in warm waters, so it's typically AL80's.

I have my own gear and that has helped me with being able to dial in my weight perfectly. I usually use 2 2lb weights in 2 trim pockets, but they did not have any of those on this trip and only had 3lb weights. Those unfortunately wouldn't fit in my trim pockets so I had to wear a belt with 6lbs which put me slightly over weight.

But the guide commented on my trim and buoyancy and said they were both pretty good especially considering my experience level.

I actually plan on buying 2 2lb weights that I can bring with me now so that I never have this problem again. I pack my SCUBA gear in a carry on so weight isn't an issue.

On a side note, it was funny seeing experienced diver think my BP/W setup was some super special fancy BCD. The captain and guide also thought it was super expensive then I told them it was probably cheaper than their rental BCD's and they were like woah really?
 
This question comes up all the time, try looking at air consumption in the search bar. Buoyancy, trim, propulsion, relaxation, and experience, all play a role in gas consumption. I'm an old man, slightly smaller than you, I get more than an hour out of an AL80 at 60 ft, no problem. Breathe in slow, pause briefly with an open glottis, exhale slowly and take another breath. It becomes 2nd nature after a short time. Work on the other variables I have mentioned. You'll do better with more experience and comfort.
 
I think that you are overthinking about this and just need to get more experience. My husband and I were both air hogs in the beginning, but with lots of diving we improved a lot and finish dives because we get near our NDL, but still have lots of air left. We also try to keep as fit as we possibly can, which really helps. Before we learned to dive I had lost possibly 14 pounds or more. This also made a big difference.

Just do as much diving as you possibly can and when you are not diving get out there and get as much exercise as you can.

Best fishes x
I exercise regularly so this is my "off" week when it comes to that, as when I am on vacation, there is no work or exercise. My body needs a breather from all the wear and tear I put on it in the weight room. I do a pretty intense workout of high rep that is kind of like cardio too because I time my resting states and also super set a bit.

I got certified this year and with that and post dives I have done 15 so I'm hoping to do at least that per year from here on out. I hope to do some local diving too once this dive site opens up this summer.
 
This question comes up all the time, try looking at air consumption in the search bar. Buoyancy, trim, propulsion, relaxation, and experience, all play a role in gas consumption. I'm an old man, slightly smaller than you, I get more than an hour out of an AL80 at 60 ft, no problem. Breath in slow, pause briefly with an open glottis, exhale slowly and take another breath. It becomes 2nd nature after a short time. Work on the other variables I have mentioned. You'll do better with more experience and comfort.
Not sure what "open glottis" is but will google it. But it sounds like you are saying to hold your breath slightly, which I thought was a huge no-no. I mean I understand if you aren't changing depth that you don't really have much to worry about, but just generally speaking, it kind of sounds like you are saying to do a slight holding of breath to get a little bit more time per breath, which would add up over time.
 
Many variables to air consumption.

Body mass
Relaxation level
Temperature
Depth
Trim
Exertion level
Fitness level
Breathing efficiency.

My best ever consumption was 0.36 cuft/min warm water zero exertion, worst was 0.95 cuft/min cold water, shivering, turned out i had a 101 fever when I got home.
I usually run 0.5-0.6 warm and 0.6-0.7 cold.
6 ft and 185 lbs

My girlfriend consistently has much lower gas consumption than me.
I have started just opting for a larger tank when I can which keeps us closer to even.
I dive a 100, she dives an 80
 
Hi @purbeast
I have exercised 6-7 days per week my entire adult life, I believe that it helps. I was a competitive swimmer much of my younger life, I think that helped also. No, it's not breath holding, just a short pause. This breathing pattern is the opposite to what you use on land,. efficient for gas exchange underwater.
 

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